Multiple alternative material blockouts have shown to perform similarly to wood blockouts (both in testing and in practice). As such, MwRSF does not have concerns with using blockouts made from other materials as long as the are the same size as the wood blockout it is replacing, and the alternative blockout has the strength to keep its shape during impact events.

There have been multiple proprietary blockouts made from plastics and/or composite materials that have been shown to have adequate strength to perform similarly to wood blcokouts. Additionally, steel tube blockouts could also be utilized as alternatives to wood blockouts (steel tube blockouts are regularly used in some thrie-beam transition designs).

Conversely, steel I-shaped blockouts have caused issues in the past. With only a thin web between the front and back flanges, steel I-shaped blockouts have been shown to bend and fold over during impacts, effectively reducing the offset distance between rail and post. As a result, steel I-shaped blockouts can cause increased snag and increased risk of rail tearing due to rail contact with the post flange edges. Thus, the use of steel I-shaped blockouts is not recommended without further evaluation.

Disclaimer:
The information contained on the Midwest Roadside Safety Facility (MwRSF) website is subject to change without prior notice. The University of Nebraska and the MwRSF is not responsible or liable, directly or indirectly, for any damage or loss caused or alleged to be caused by or in connection with the use or misuse of or reliance upon any such content, goods, or services available on this site.